Sofa



FIG. 1 is a front elevation view of a sofa in accordance with the new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevation view thereof, an opposite side elevation view being a mirror image thereof; and,

FIG. 4 is a back elevation view thereof.

The broken lines on the sofa are understood to represent stitching. 

The ornamental design for a sofa, as shown and described. 